The so-called Cushing reflex has been suggested to explain arterial hypertension. According to this mechanism, hypoperfusion of the rostroventral medulla induces sympathetic nervous system activation and a pressor response. The pressor response then increases perfusion of a primary brain area regulating sympathetic activity, but in doing so heightens systemic blood pressure. The initial hypoperfusion could arise as a result of narrowed vertebral arteries—evident as high resistance and low flow in these arteries. Although systemic hypertension might lead via remodeling to a narrowing of vertebral arteries, it has been suggested that hypertension is the result of narrowed vertebral arteries rather than the cause 1).
Cushing response categorization helps in identifying critical conditions and predicting outcome 2)